It might be able to mount and string these rackets. The upgrades (if I remember correctly), were to allow the wide body rackets. The head mounting device, was not able to go up high enough when the Wilson and other wide body rackets started coming out. I would think it could mount a midsize frame. I can't remember the bottom mounting.

The upgrade also include the longer guide rails for the mains. I think the smaller 2 cross clamps pretty much remained the same.

From the information, I would think you probably could do a mid sized racket. Once potential problem, might be getting the clamp close enough to the edge on some of the mains. Some will disagree, but you could use a floating clamp for the longest mains, as the mains get shorter the regular glide bars should work.